There's probably no agreed-upon formal definitions. Informally, power consumption would mean the total power consumption of a device. Power dissipation usually connotes that power that is consumed by things not related to the desired task at hand.

Example: the current in a motor's winding is used to generate a magnetic field. This requires a total power. Some of that power is dissipated in the conductor's resistance as heat, producing no useful work.

Power dissipation most often indicates the amount of power wasted as heat by a given device. That is normally what is meant when an electronic device is given a maximum power dissipation rating. Other forms of useless dissipation are possible, but not usually significant.

The (total) power consumed by the device may be much greater than its own dissipation, for instance a voltage converter operating at 90% efficiency might consume 10W, deliver 9W output, and dissipate 1W of heat.